<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>四级备考助手</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Arial', sans-serif;
        }
        
        body {
            background-color: #f5f7fa;
            color: #333;
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }
        
        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 0;
            border-bottom: 1px solid #e0e0e0;
            margin-bottom: 30px;
        }
        
        .logo {
            font-size: 24px;
            font-weight: bold;
            color: #4285f4;
        }
        
        .user-info {
            display: flex;
            align-items: center;
        }
        
        .user-avatar {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background-color: #e0e0e0;
            margin-right: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
        }
        
        .main-content {
            display: grid;
            grid-template-columns: 250px 1fr;
            gap: 20px;
        }
        
        .sidebar {
            background-color: white;
            border-radius: 8px;
            padding: 20px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
        }
        
        .sidebar-menu {
            list-style: none;
        }
        
        .sidebar-menu li {
            margin-bottom: 15px;
        }
        
        .sidebar-menu a {
            display: flex;
            align-items: center;
            color: #555;
            text-decoration: none;
            padding: 8px 12px;
            border-radius: 4px;
            transition: all 0.3s;
        }
        
        .sidebar-menu a:hover, .sidebar-menu a.active {
            background-color: #f0f7ff;
            color: #4285f4;
        }
        
        .sidebar-menu i {
            margin-right: 10px;
            font-size: 18px;
        }
        
        .content-area {
            background-color: white;
            border-radius: 8px;
            padding: 30px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
        }
        
        .section-title {
            font-size: 22px;
            margin-bottom: 25px;
            color: #333;
            display: flex;
            align-items: center;
        }
        
        .section-title i {
            margin-right: 10px;
            color: #4285f4;
        }
        
        /* 单词卡片样式 */
        .word-card {
            background-color: #f9f9f9;
            border-radius: 8px;
            padding: 25px;
            margin-bottom: 20px;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
        }
        
        .word-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 15px;
        }
        
        .word {
            font-size: 28px;
            font-weight: bold;
            color: #333;
        }
        
        .phonetic {
            color: #666;
            font-size: 16px;
            margin-left: 10px;
        }
        
        .word-type {
            display: inline-block;
            background-color: #e0e0e0;
            color: #555;
            padding: 3px 8px;
            border-radius: 4px;
            font-size: 12px;
            margin-right: 5px;
        }
        
        .meaning {
            margin: 15px 0;
            line-height: 1.6;
        }
        
        .example {
            background-color: #f0f7ff;
            padding: 12px 15px;
            border-radius: 6px;
            margin: 10px 0;
            border-left: 3px solid #4285f4;
        }
        
        .example p {
            margin: 5px 0;
        }
        
        .example-translation {
            color: #666;
            font-size: 14px;
        }
        
        .word-actions {
            display: flex;
            justify-content: space-between;
            margin-top: 20px;
        }
        
        .btn {
            padding: 8px 16px;
            border-radius: 4px;
            border: none;
            cursor: pointer;
            font-size: 14px;
            transition: all 0.3s;
        }
        
        .btn-primary {
            background-color: #4285f4;
            color: white;
        }
        
        .btn-primary:hover {
            background-color: #3367d6;
        }
        
        .btn-outline {
            background-color: transparent;
            border: 1px solid #ddd;
            color: #555;
        }
        
        .btn-outline:hover {
            background-color: #f5f5f5;
        }
        
        /* 进度统计 */
        .stats-cards {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 20px;
            margin-bottom: 30px;
        }
        
        .stat-card {
            background-color: white;
            border-radius: 8px;
            padding: 20px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
            text-align: center;
        }
        
        .stat-number {
            font-size: 32px;
            font-weight: bold;
            color: #4285f4;
            margin: 10px 0;
        }
        
        .stat-title {
            color: #666;
            font-size: 14px;
        }
        
        /* 学习计划 */
        .plan-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px;
            border-bottom: 1px solid #f0f0f0;
        }
        
        .plan-item:last-child {
            border-bottom: none;
        }
        
        .plan-info {
            flex: 1;
        }
        
        .plan-title {
            font-weight: 500;
            margin-bottom: 5px;
        }
        
        .plan-desc {
            color: #666;
            font-size: 14px;
        }
        
        .progress-bar {
            height: 6px;
            background-color: #e0e0e0;
            border-radius: 3px;
            margin-top: 10px;
            overflow: hidden;
        }
        
        .progress {
            height: 100%;
            background-color: #4285f4;
            border-radius: 3px;
        }
        
        /* 选项卡样式 */
        .tabs {
            display: flex;
            border-bottom: 1px solid #e0e0e0;
            margin-bottom: 20px;
        }
        
        .tab {
            padding: 10px 20px;
            cursor: pointer;
            color: #555;
            border-bottom: 2px solid transparent;
            transition: all 0.3s;
        }
        
        .tab.active {
            color: #4285f4;
            border-bottom: 2px solid #4285f4;
        }
        
        .tab-content {
            display: none;
        }
        
        .tab-content.active {
            display: block;
        }
        
        /* 真题练习 */
        .question-card {
            background-color: white;
            border-radius: 8px;
            padding: 25px;
            margin-bottom: 20px;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
        }
        
        .question-text {
            font-size: 16px;
            line-height: 1.6;
            margin-bottom: 20px;
        }
        
        .options {
            margin-bottom: 20px;
        }
        
        .option {
            display: block;
            margin-bottom: 10px;
            padding: 10px 15px;
            background-color: #f5f5f5;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .option:hover {
            background-color: #e0e0e0;
        }
        
        .option.selected {
            background-color: #e3f2fd;
            border-left: 3px solid #4285f4;
        }
        
        .option.correct {
            background-color: #e8f5e9;
            border-left: 3px solid #4caf50;
        }
        
        .option.incorrect {
            background-color: #ffebee;
            border-left: 3px solid #f44336;
        }
        
        .explanation {
            margin-top: 20px;
            padding: 15px;
            background-color: #f5f5f5;
            border-radius: 4px;
            display: none;
        }
        
        .explanation-title {
            font-weight: bold;
            margin-bottom: 10px;
        }
        
        /* 响应式设计 */
        @media (max-width: 768px) {
            .main-content {
                grid-template-columns: 1fr;
            }
            
            .stats-cards {
                grid-template-columns: 1fr;
            }
        }
    </style>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css">
</head>
<body>
    <div class="container">
        <header>
            <div class="logo">四级备考助手</div>
            <div class="user-info">
                <div class="user-avatar">
                    <i class="fas fa-user"></i>
                </div>
                <span>学习者</span>
            </div>
        </header>
        
        <div class="main-content">
            <div class="sidebar">
                <ul class="sidebar-menu">
                    <li><a href="#" class="active"><i class="fas fa-home"></i> 学习首页</a></li>
                    <li><a href="#"><i class="fas fa-book"></i> 单词记忆</a></li>
                    <li><a href="#"><i class="fas fa-clipboard-list"></i> 真题练习</a></li>
                    <li><a href="#"><i class="fas fa-chart-line"></i> 学习进度</a></li>
                    <li><a href="#"><i class="fas fa-calendar-alt"></i> 学习计划</a></li>
                    <li><a href="#"><i class="fas fa-cog"></i> 设置</a></li>
                </ul>
            </div>
            
            <div class="content-area">
                <div class="section-title">
                    <i class="fas fa-home"></i> 学习首页
                </div>
                
                <div class="stats-cards">
                    <div class="stat-card">
                        <i class="fas fa-book-open" style="font-size: 24px; color: #4285f4;"></i>
                        <div class="stat-number">328</div>
                        <div class="stat-title">已学单词</div>
                    </div>
                    <div class="stat-card">
                        <i class="fas fa-check-circle" style="font-size: 24px; color: #4285f4;"></i>
                        <div class="stat-number">85%</div>
                        <div class="stat-title">记忆率</div>
                    </div>
                    <div class="stat-card">
                        <i class="fas fa-clock" style="font-size: 24px; color: #4285f4;"></i>
                        <div class="stat-number">15</div>
                        <div class="stat-title">学习天数</div>
                    </div>
                </div>
                
                <div class="tabs">
                    <div class="tab active" data-tab="word">今日单词</div>
                    <div class="tab" data-tab="question">真题练习</div>
                    <div class="tab" data-tab="plan">学习计划</div>
                </div>
                
                <div class="tab-content active" id="word-tab">
                    <div class="word-card">
                        <div class="word-header">
                            <div>
                                <span class="word">perspective</span>
                                <span class="phonetic">/pərˈspektɪv/</span>
                            </div>
                            <span class="word-type">n.</span>
                        </div>
                        
                        <div class="meaning">
                            <p>观点，看法；透视法</p>
                        </div>
                        
                        <div class="example">
                            <p>From an economic perspective, the policy makes sense.</p>
                            <p class="example-translation">从经济角度来看，这项政策是有道理的。</p>
                        </div>
                        
                        <div class="word-actions">
                            <button class="btn btn-outline"><i class="far fa-bell"></i> 标记</button>
                            <div>
                                <button class="btn btn-outline"><i class="fas fa-volume-up"></i> 发音</button>
                                <button class="btn btn-primary">记住了</button>
                            </div>
                        </div>
                    </div>
                    
                    <div class="word-card">
                        <div class="word-header">
                            <div>
                                <span class="word">sustain</span>
                                <span class="phonetic">/səˈsteɪn/</span>
                            </div>
                            <span class="word-type">v.</span>
                        </div>
                        
                        <div class="meaning">
                            <p>维持，保持；支撑</p>
                        </div>
                        
                        <div class="example">
                            <p>The boat couldn't sustain the weight of more than ten people.</p>
                            <p class="example-translation">这艘船无法承受超过十个人的重量。</p>
                        </div>
                        
                        <div class="word-actions">
                            <button class="btn btn-outline"><i class="far fa-bell"></i> 标记</button>
                            <div>
                                <button class="btn btn-outline"><i class="fas fa-volume-up"></i> 发音</button>
                                <button class="btn btn-primary">记住了</button>
                            </div>
                        </div>
                    </div>
                    
                    <div style="text-align: center; margin-top: 20px;">
                        <button class="btn btn-primary"><i class="fas fa-random"></i> 换一组单词</button>
                    </div>
                </div>
                
                <div class="tab-content" id="question-tab">
                    <div class="question-card">
                        <div class="question-text">
                            The professor's lecture ________ the importance of cultural diversity in the modern workplace.
                        </div>
                        
                        <div class="options">
                            <div class="option" data-correct="true">A. highlighted</div>
                            <div class="option">B. illuminated</div>
                            <div
